Budget planning. Cost calculation

Hello, after comparing for months now and getting a few offers, we think we have found the right thing. It should be a prefabricated house.

What still concerns me is whether we are calculating the costs correctly.

Budget 370,000€
Offer for house with slab foundation (we do not want a basement)
192,000€ 146m² with own work that we have to do (floors, wallpapering, sanitary facilities, floors, doors)
Material for own work: according to house provider 13,000€ (seems tight to me?)
Extra charge for possible upgrades of the house’s standard equipment: 5,000€
Plot with notary: 96,500€
Additional construction costs: 30,000€
Kitchen: 10,000€
Furniture: we have everything
Garage: not planned for now
Stove: no idea - 1,000€
There remain 35,000€ for miscellaneous (terrace and garden as own work)
Is that realistic?

The upgrades from the standard seem a bit tight to me. I don't know what the house standard is and what is okay for you, but so far we have had upgrades for the roof tiles, the windows (lower lights, insect screen roller blinds, electric shutters), the front door, the interior doors, etc., and have already paid significantly more than the 5,000,- not to mention the electrical work. Alone there, probably a large part of your budget will be spent.

13,000,- for materials also seems tight to me. But as I said, you can't really say that in general. Because one person wants gold-plated faucets, another is fine with the cheapest from the hardware store. It depends on how high you set your expectations.

Kitchen? 10,000 euros? How big?

Will you tell us which manufacturer you are building or planning to build with?

do you think the kitchen is also too tight? it should be an open modern kitchen, but installed by ourselves. we have connections for the electrical appliances and get a good deal there. may i mention the company here? it should be hanlo house ok we still have 35,000eur for other things, we could use some of that. we are doing the garden ourselves, so we only need material costs, we don't want anything complicated

Electric roller shutters and such gimmicks we don't need

The hardware store is fine. It should be a walk-in shower and modern, but not the most expensive.

It's more the case with us that we could invest more in the house, but we actually don't want to, because we don't want to live just for the house but also want to live well. I was just unsure whether we are so realistic with normal expectations.